A 50-year-old man with motor neurone disease presents to hospital with respiratory distress following two (2) days of fever and malaise. He is alert and anxious, and an arterial blood gas performed on oxygen (8L/min semi-rigid mask) revealed PaO2 45 mmHg, PaCO2 65 mmHg, pH 7.36 and HCO3 36 mmol/L. He has used a motorised wheelchair for three (3) years but continues to work as an accountant. His attentive wife states that they have discussed mechanical ventilation and are keen for him to receive full Intensive Care support.

• On day 7 of his admission he become febrile, develops a leukocytosis and a chest x-ray shows a new infiltrate in his left lower lobe. Discuss the investigation and management of this problem.

College Answer

Unfortunately nosocomial pneumonia is a common sequelae of mechanical ventilation after 7 days. A standard approach should be considered, which must include some culturing of secretions (tracheal aspirates, or more invasive eg. bronchoscopic lavage or protected brush). Gram stain may provide quantitative information of potential pathogens, as may quantitative cultures. Antibiotics should be introduced if bacterial aetiology suspected, and should be appropriate to local factors (including usual bacterial sensitivities, previous antibiotic use and unit protocols) but should include cover for MRSA and resistant gram negatives for a specified period of time (eg. 3 days and review). Plan for review of antibiotics should be discussed. Differential diagnosis includes other causes of WCC/temperature elevation (eg. line sepsis, UTI, sinus infection, pulmonary embolus, myocardial infarction etc.) and other causes of infiltrates (eg. collapse/atelectasis, pulmonary oedema and pulmonary embolus) and each may require specific investigation and treatment depending on other clinical information. This event provides another opportunity to revisit the direction of management when necessary discussion regarding developments occurs with wife and family.